The invention relates to hollow articles of the type wherein one or more internal spaces or cavities are surrounded by separately produced sections which are sealingly secured to each other. Examples of such hollow articles are intake manifolds of motor vehicles.
In accordance with a presently known proposal, intake manifolds are produced by casting in iron molds with sand cores. A drawback of such practice is that the manifolds are expensive in view of the need to destroy the cores. In addition, the internal surfaces of the thus obtained manifolds are not sufficiently smooth . to ensure turbulence-free inflow of air or another fluid so that it is necessary to resort to a secondary treatment which contributes to the cost of the manifolds.
It was also proposed to make sections of intake manifolds in reusable molds in die casting machines and to weld the sections to each other subsequent to setting of their material. This results in the making of manifolds with reasonably smooth internal surfaces; however, the welding operation contributes significantly to the cost of the ultimate product.